Expert / 16 October, 2022 / My Baba

The 20-Week Ultrasound: What To Expect From The Anomaly Scan

As you approach the 20-week mark, the NHS offer expectant mums a more detailed scan as part of your pre-natal care. The 20-week scan or anomaly ultrasound can offer reassurance and detect some abnormalities. Window to the Womb tell us what to expect.

What IS the 20 week scan?

We get many questions on the 20-week scan (especially from first-time parents). We wanted to offer you more information on this important mum-to-be milestone.

The 20-week scan is a screening test, performed using an ultrasound machine which checks for possible physical problems with baby. This scan is offered to all ladies, but not everyone will choose to have it. It is a positive experience for most people, but not for everybody. Remember – if you decide not to have the scan your choice will be respected.

The objectives of the ultrasound scan are to:

• offer screening to eligible women in England to identify anomalies that are life limiting
• identify issues which may benefit from antenatal treatment
• identify anomalies which require early intervention following delivery
• to provide choice in appropriate testing for you and your requirements and help manage your pregnancy

You can expect to spend 30-45 minutes at your appointment. The scan should incorporate pre-scan counselling, the initial ultrasound examination, counselling following your appointment, as well as a full report on your scan. If you’re expecting multiple babies, then your appointment may be slightly longer due to additional time needed. Healthcare professionals do have a duty of care to report any findings, so many women who do not wish to be informed of any anomalies, often choose not to have a 20-week scan.

The sonographer will look at the following:

1. The skull and brain
2. View of the lips and nasal tip
3. The chest and lungs
4. The heart
5. Abdominal contents which includes: stomach, abdominal wall and cord insertion, diaphragm, kidneys and bladder
6. The whole of the spine and examination of the skin covering
7. All four limbs
8. Uterine cavity for placenta and amniotic fluid

The 11 conditions currently screened for:

• Anencephaly
• Open spina bifida
• Cleft lip
• Diaphragmatic hernia
• Gastroschisis
• Exomphalos
• Serious cardiac abnormalities
• Bilateral renal agenesis
• Lethal skeletal dysplasia
• Edwards’ syndrome (Trisomy 13)
• Patau’s syndrome (Trisomy 18)

Finding out the sex of your baby:

Interestingly, there is no requirement to determine the gender at your 20-week scan, as the primary purpose is to look for anomalies and some hospitals do not include this information readily in your scan. This is why we have additional services for gender confirmation from 16 weeks (four weeks before your NHS appointment). We offer sexing scans from this gestation to ensure 99.9% accuracy, as any time before this can mean the accuracy rate decreases. Although the primary purpose of our scans is the well-being of mum and baby; our sonographers are additionally trained to find out if you’re having a little boy or girl.

There is no magic touch to determine gender of baby and it is totally dependent upon the baby having their legs wide open, in the correct position (on their side) and identifying a penis or the labia in between the legs. It can take up to 10 minutes sometimes to achieve this and there are many factors that can make gendering more difficult, such as an increased BMI, dehydration and of course – the position of baby and placenta. It’s always important to drink plenty of water before you attend a scan to ensure there’s plenty of fluid around baby.

We also understand that your pregnancy is a special time, and although many hospitals unfortunately only allow one relative or partner to attend your scan (we would recommend double-checking with your hospital beforehand), we encourage family members, children and friends to come along to share this experience with you.

Important to note:

Sources

• FASP (Fetal anomaly screening handbook)

Article by Window to The Womb